Heretofore, exploration of seabed resources such as gas hydrate has been performed by searching only geologic data under the seabed by using an audio instrument as a low-frequency sound source for seabed geology exploration.
As such a seabed resource exploration method, for example, a seismic exploration method has been used (for example, refer to http://www.mh21japan.gr.jp/ (homepage of The Research Consortium for Methane Hydrate Resources in Japan)). This is a method which is used for investigating a distribution of strata containing petroleum/natural gas in petroleum/natural gas exploration, artificially generates vibrations like that of an earthquake, explores the geology by using the vibrations, and explores the resources based on the results of the exploration.
Moreover, when certain vibrations are given in the vicinity of the surface of the sea, sound waves are generated and transmitted into the sea. A seismic reflection method for performing the exploration by using the sound waves reflected on the surface of the seabed is also used.
Furthermore, cables called streamers are used in order to receive the reflecting sound waves, and recently, a research using plural streamer cables has become not uncommon. In a recent petroleum-exploring geocentric exploration, there is also a case where ten or more streamer cables with a length of 6000 m or more are towed by ships at one time to make the research. When the plural streamer cables are used as described, solid seismic exploration records are obtained, and accordingly, such a method is called a 3D (three-dimensional) seismic exploration method.
However, the seismic exploration method does not directly confirm the resources such as the petroleum/natural gas, and the seabed is mined while assuming the presence of the resources from the results of the geology exploration. Accordingly, there are many cases where the resources do not come out even if the seabed is actually mined.
Moreover, the above-described seismic reflection method and 3D seismic exploration method have large scales, and require much expense and time.
Consequently, considering the above-described problems, it is an object of the present invention to provide a seabed resource exploration system and a seabed resource exploration method, which are highly reliable and capable of exploring the seabed resources inexpensively.